Differential pairs are used in printed circuit boards and other applications to improve noise immunity of signal connections. In a differential pair, two signal traces are in close physical proximity, generally parallel to one another and having similar physical configurations. The signal carried by the differential pair is not referenced either to ground or high voltage level as in the case of a single-ended signal. Instead, the signal is referenced to the voltage difference between signals carried on the signal traces being above a given level. In such an arrangement, electrical noise coupled to the signal traces comprising the differential pair represents common-mode noise that may cancel when a signal on a first trace of the differential pair is subtracted from a signal on the second trace of the differential pair.
Routing of differential pairs in accordance with the prior art can result in impedance mismatches with resultant bandwidth limitations. Noise and bandwidth performance of the differential pairs becomes even more critical as signal frequencies increase. Accordingly arrangements and methods are sought that improve noise and bandwidth performance of differential pairs.